Abstract: To explore the application mechanism and condition of denitrifying biological agent in saline soil remediation, aerobic denitrification capacity was used as the main index, the planting soil of greenhouse in Ningbo Cixi was used as the material, the bacterial strain was isolated by screening and comparing. An aerobic bacterial strain with the highest activities was obtained and named DPT001. The strain was identified according to its morphological, physiological and biochemical properties and 16S DNA gene sequence analysis. The suitable culture condition of this strain was studied. The results showed that DPT001 was a gram-positive bacillus and was identified as Castellaniella ginsengisoli. In the anaerobic environment, NO3- degradation rate was 92% in 52 h. The suitable growth conditions were neutral or weak alkaline soil. The pot experiment showed that the biological bacterial fertilizer (mixed with the strain and decomposed peanut shell) obviously decreased the total salt concentration and NO3- concentration. An aerobic denitrifying strain was isolated from greenhouse soil and it exhibited high denitrification characteristics and was better than the commercial denitrification biological bacterial agent.